1. Field of the Invention
The present invention concerns a vehicle seat and, particularly, it relates to a vehicle seat used outdoors and a method of manufacturing a vehicle seat, which has good finish, good physical properties, durability and weather resistance and which can be manufactured efficiently, as well as a skin material for the vehicle seat.
2. Statement of the Related Art
A vehicle seat has been formed, for example, by disposing a cushioning material on a bottom plate and covering with a skin material. For the vehicle seat, a concave/convex shape has been proposed particularly in view of aesthetics and comfort in riding. For example, a method of using a tack last technique for forming the concave/convex portion and the covering a cushioning material with a skin material by stitching have been used in manufacturing seats of concave/convex shape.
In the tack last method, as shown in FIG. 10, a concave line is formed to a cushioning material 120 and a skin material 110 is tack lasted by a tack last means (tack last string) 140 to a bottom plate 130.
The tack last seat described above involves a problem in that a distinct feeling for the concave/convex shape can not be obtained when the concave line forms a complicated curve (such as an S-shaped curve) or a three dimensional curve, unless many tack last points are set on every turning point of the curve.
However, if the number of tack last points is increased in order to overcome the above-described problem, the result is a dimple-like appearance of the outer surface, as well as less efficiency in the assembling operation. Further, since the tack last portions receive concentrated forces, the skin material and the tack last means are sometimes detached.
The method of covering a cushioning member 120 with a skin material 110 having the concave/convex shape formed by stitching suffer from the drawback that the skin material 120 and the cushioning material 120 separate at the concave/convex portion, particularly, at the concave portion.
In order to solve the foregoing problem, vehicle seats have been formed by applying an adhesive to the seating area of the cushioning material and bonding the skin material thereto. In this vehicle seat, the adhesive is applied to predetermined portions including ridges of the cushioning material.
However, when a rider sits on the seat, since the load is concentrated on the ridges of the cushioning material where the skin material is secured, excessive force is exerted on the skin material to undesirably flex or crease the seat.
Further, in covering the cushioning material 120 with the skin material 110, it is necessary to prevent water and dust from entering into the cushioning material 120 where the skin materials 110 are joined to each other by stitching. For this purpose, a water proof film (not illustrated) is disposed between the skin material 110 and the cushioning material 120 at the stitched portions of the skin material 110 to prevent intrusion of rain water or the like.
In using the water proof film described above, it is necessary to dispose the water proof film accurately to prevent water and dust from intruding.
Further, in a vehicle seat formed by covering the cushioning material 120 with the skin material 110 by stitching, since the skin material 110 and cushioning material 120 tend to separate at the concave/convex portions, particularly, at concave portions, in one method an adhesive is applied between the skin material 110 and the cushioning material 120 to prevent separation.
When the adhesive is applied between the skin material 110 and the cushioning material 120, if the water proof film is not disposed at an appropriate position, the water proof film comes into the region of the adhesive and become twisted or the water proof film, if between the adhesive and the skin material 110, interferes with the adhesion between the skin material 110 and the cushioning material 120.
Therefore, it is necessary to accurately cut off the water proof film at exact positions, but the operation while confirming the cut off position is laborious and inefficient.
Further, the vehicle seat is generally formed as an integral cellular molding comprising a skin material, a cushioning material and a bottom plate, for example, a polyvinyl chloride skin material and a polyurethane cellular material.
As shown, for example, in FIG. 15 and FIG. 16, the vehicle seat comprises a skin material 110 and a cushioning material 120, and the skin material 110 includes an acrylic material 111 applied to a synthetic resin 112 or to a synthetic resin 112 laminated on a substrate fabric 113. Then, the skin material 110 is bonded to the surface of the synthetic resin 112 or the substrate fabric 113 using an adhesive 140.
In the prior art described above, if a polyvinyl chloride skin material is used, for example, as the synthetic resin 112, an undesirable vinyl resin-like gloss appears on the surface.
Further, contact between the skin material 110 and the cushioning material 120 results in the following disadvantages.
(1) A plasticizer contained in the synthetic resin 112 migrates to and degrades the cushioning material 120.
(2) When a plasticizer contained in the synthetic resin 112 migrates to the cushioning material 120, the amount of the plasticizer contained in the synthetic resin 112 is decreased to make the synthetic resin 112 hard and to worsen the feel upon sitting on the seat.
(3) Amine catalyst contained in the cushioning material 120 adversely affects the synthetic resin 112 to cause discoloration or fading of the synthetic resin 112, thereby detracting from the aesthetic appearance of the vehicle seat.
(4) If a solvent type adhesive is used as the adhesive 140 for bonding the skin material 110 to the cushioning material 120, the solvent contained in the adhesive migrates to the synthetic resin 112 to discolor the synthetic resin 112.
For overcoming the drawbacks described above, a method has been developed for preventing migration of the plasticizer or the amine catalyst, which method involves placing an amide type resin film or a polyethylene type resin film between the skin material and the cushioning material, but this method increases the number of components, makes the manufacturing cost expensive and increases the number of steps.
An object of the present invention is to provide a vehicle seat in which a water proof film is disposed accurately at stitched portions of a skin material covering a cushioning material and reliably preventing water or dust from intruding through the stitched portions of the skin material, as well as to provide a method of manufacturing such a vehicle seat.
Another object of the present invention is to provide a vehicle seat with a preferred finish, having high durability and capable of being manufactured efficiently, as well as to provide a method of manufacturing such a vehicle seat.
A further object of the present invention is to provide a skin material for use in a vehicle seat having a satisfactory appearance, and capable of preventing a plasticizer contained in the synthetic resin of the skin from migrating into the cushioning material without increasing the number of components or number of steps, thereby preventing an uncomfortable feeling upon sitting on the seat and degradation of the cushioning material.
A further object of the present invention is to provide a skin material for use in a vehicle seat free from the worry of discoloration or fading of the skin material caused by an amine catalyst contained in the cushioning material.
A further object of the present invention is to provide a skin material for use in a vehicle seat capable of resisting discoloration by migration of a solvent to the skin material when a solvent type adhesive is used for bonding the skin material to the cushioning material.
A still further object of the present invention is to provide a skin material for use in a vehicle seat that can be bonded by high frequency welding.
A still further object of the present invention is to provide a skin material for use in a vehicle seat having a satisfactory leather-like feeling, with no loss of comfort due to abrupt shifting of load when a rider sits on the seat and high resistance to weathering.
In the present specification, xe2x80x9cvehicle seatxe2x80x9d includes seats for land motorcycles and scooters, as well as snowmobiles and water motorcycles and, further, includes vehicle seats for tricycle buggy vehicles, mounting vehicles and construction machine seats.
The present invention is to be explained with reference to embodiments based on claims.
FIGS. 1 and 2 show a vehicle seat S in accordance with an embodiment of the present invention, as including a cushioning material 20 disposed on a bottom plate 30 and the cushioning material 20 covered with a skin material 10.
The skin material 10 and the cushioning material 20 are bonded with an adhesive 40 coated in a region 50, inward of a ridge 23, which forms a seating area of the cushioning material 20. The adhesive 40 is coated on one or both of the skin material 10 and the cushioning material 20.
When the skin material and the cushioning material are bonded by the adhesive in this way, the adhesive facilitates the assembling of the cushioning material and the skin material.
Further, since the adhesive is coated in a region inward of the ridge for the cushioning material, the skin material is not secured at the ridge portion which receives the most localized load, so that no excessive force is exerted on the skin material, thereby preventing flexion and creasing, and providing a vehicle seat of good appearance.
Further, the skin material 10 is formed by joining a skin material 10a for the seating area and a skin material 10b surrounding the seating area. By stitching of a plurality of skin materials in this way it is possible to form a desired concave/convex shape.
As shown in FIGS. 3 and 4, a concave groove 22 is formed along a line 10c joining the skin material 10a and the skin material 10b,on the side of the ridge 23 adjacent the cushioning material 20. Then, a water proof film 21 is disposed between the skin material 10 and the cushioning material 20 and extending from the skin material 10b to the concave groove 22.
As described above, in the vehicle seat of this embodiment, since the concave groove is formed at a predetermined position including the joining line on the side of the ridge adjacent the cushioning material, the water proof film can be appropriately positioned by disposing the water proof film against that portion of the skin material which surrounds (excludes) the seating area to the concave groove, with the concave groove serving as a guide line.
The skin material 10 comprises a PVC layer 12, a substrate fabric 13 composed of a knitted material and a closed-cell cellular synthetic resin 14, laminated in this order, and an acrylic or vinyl chloride type surface material 11 applied over the PVC layer 12.
As described above, since the surface material 11 is disposed on the PVC layer 12, embossing can be applied to the surface material 11, thereby providing the seat surface with a leather-like feel to obtain a satisfactory vehicle seat having good appearance.
When a vinyl chloride-acrylate copolymer resin or a vinyl chloride-methacrylate copolymer resin is used as the surface material 11, high frequency welding can be used to secure the skin materials 10 to each other or to secure the periphery of the skin material 10 to the bottom plate 30 reliably and easily.
The substrate fabric 13 is a knitted material made of at least one of nylon yarns, polyester yarns and rayon yarns.
Since the substrate fabric 13 is disposed adjacent the PVC layer 12, when the skin material 10 is pulled, no direct force is applied to the closed-cell cellular material 14 and breakage of the closed-cell cellular material 14 is thereby prevented.
Further, since the closed-cell cellular material 14 is present between the PVC layer 12 of the skin material 10 and the cushioning material 20, the plasticizer contained in the PVC layer 12 cannot migrate through the substrate fabric 13 to the cushioning material 20, thereby preventing degradation of the cushioning material 20.
Further, since the closed-cell cellular material 14 is present between the PVC layer 12 and the cushioning material 20, because the plasticizer contained in the PVC layer 12 can not migrate through the substrate fabric 13 to the cushioning material 20, hardening of the PVC layer due to a decrease of the plasticizer is prevented.
Further, since the closed-cell cellular material 14 is present between the PVC layer 12 and the cushioning material 20, an amine catalyst contained in the cushioning material 20 can not migrate into the PVC layer 12 to cause it to discolor or fade. In this way, it is possible to prevent deterioration of the aesthetic appearance of the vehicle seat upon constant exposure to the weather.
Further, since the cellular material 14 with a closed-cell structure is present between the PVC layer 12 and the cushioning material 20, a solvent contained in the adhesive for bonding the skin material 10 to the cushioning material 20 can not migrate into the PVC layer 12 to discolor the PVC layer 12.
The closed-cell cellular material 14 may suitably be a crosslinked cellular material and, more specifically, a PVC cellular material.
Crosslinked cellular material has heat resistance and shows excellent weather resistance when exposed to broiling temperatures for a long period of time.
Further, use of the PVC cellular material as the closed-cell cellular material 14 can reliably cover the cushioning material 20 of poor water resistance, thereby ensuring the weather resistance of the seat. Further, this can provide a satisfactory leather-like feel to the skin material.
Furthermore, since the laminate of the cushioning closed-cell cellular material 14 on the cushioning material 20 moderates impact shock, shocks to the rider are moderated. Furthermore, it prevents degradation by abrupt shifting of load upon sitting provides high durability.
The skin material 10 may contain a protein material to give the surface of the vehicle seat a smooth and fresh feeling, rather than a sticky feeling. Further, the protein prevents undesirable moisture on the seat and facilitates cleaning the seat surface. Furthermore, it also provides a moderate gloss to the surface of the seat and thereby improves the aesthetic appearance of the seat.
The method of manufacturing the vehicle seat comprises the following steps.
First, an adhesive 40 is coated over an area of the cushioning material 20 inward of ridge 23, i.e., over the seating area. Further, an adhesive 40 is coated on the surface area of skin material 10 which comes into the contact with the region inward of the ridge 23, i.e., with the seating area of the cushioning material 20.
Then, the skin material 10 and the cushioning material 20 are press-bonded to cover the cushioning material 20 with the skin material 10.
Alternatively, vacuum forming of skin material 10 may be used, with the coating of an adhesive 40 on the region inward of the ridge 23 (the seating area) of the cushioning material 20. The surface of the skin material 10 is then brought into contact with the adhesive coated region of the cushioning material 20, and then press bonded thereto, thereby covering the cushioning material 20 with the skin material 10.
As described above, by vacuum formation of the skin material, it is possible to cope with even a cushioning material of an abrupt concave/convex shape, thus ensuring freedom of design and performance.
Alternatively, a concave groove 23 may be formed in cushioning material 20 on the side facing skin material 10 and at a predetermined position along joining line 10c for the skin material 10.
Then, a water proof film 21 is attached to the cushioning material 20 and cut off along the concave groove 23.
Then, an adhesive 40 is coated on the surfaces of the cushioning material 20 and the skin material 10 in contact with each other to press-bond the skin material 10 and the cushioning material 20.
As described above, in the method of manufacturing the vehicle seat according to the present invention, a concave groove is formed in the cushioning material, and the water proof film can be disposed at an appropriate position by merely cutting off the water proof film along the concave groove with the concave groove serving as a guide line, to improve efficiency.